Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 19,292	$ 21,692
Short-term investments	32,922
Accounts receivable, net	6,792	3,322
Inventory	5,716	5,380
Prepaid expenses and other	2,820	1,320
Total current assets	67,542	31,714
Restricted cash	180	180
Deferred offering costs		1,765
Property and equipment, net	3,223	3,674
Other assets	348	73
Total assets	71,293	37,406
Current liabilities:
Accounts payable	2,874	2,865
Accrued liabilities	6,419	4,481
Deferred revenue, current portion	1,192	878
Deferred rent, current portion	598	764
Long-term debt, current portion	4,405	2,789
Total current liabilities	15,488	11,777
Deferred revenue, net of current portion	604	362
Deferred rent, net of current portion	1,502	1,903
Long-term debt, net of current portion	13,808	9,970
Preferred stock warrant liability		3,532
Total liabilities	31,402	27,544
Mandatorily redeemable convertible preferred stock, $0.0001 par value per share, 8,979 shares authorized; none and 8,118 shares issued and outstanding, respectively		103,622
Stockholders' deficit
Preferred stock, $0.0001 par value, 15,000 shares authorized; none issued
Common stock, $0.0001 par value, 150,000 shares authorized; 14,616 and 411 shares issued and outstanding, respectively	1
Additional paid-in-capital	157,890
Other comprehensive income	5
Accumulated deficit	(118,005)	(93,760)
Total stockholders' equity (deficit)	39,891	(93,760)
Total liabilities, mandatorily redeemable convertible preferred stock and stockholders' equity (deficit)	$ 71,293	$ 37,406